Manhole-cover.



No; 790,034. PATENTBD MAY 16, 1905. 0. H. DAVISON.

MANHOLE COVER.

APPLIGATI'ON FILED -TAN..15. 1904.

UNITED STATES Patented May 16, 1905.

ORIN H. DAVISON, OF CHICAGO, ILLINOIS.

MANHOLE-COVER.

SPECIFICATION forming part of Letters Patent No. 790,034, dated May 16,1905. Application filed January 15, 1904. Serial No. 189,172.

To all whom, it mli'ty concern:

Be it known that I, ORIN H. DAVISON, a citizen of the United States ofAmerica, and a resident of Chicago, in the county of Cook and State ofIllinois, have invented certain new and useful Improvements inManhole-Covers, of which the following is a specification.

The main object of my invention is to provide an improved form oflocking device for securing'the cover-plates upon manholes leading tounderground areaways, &c. I accomplish this object by the device shownin the I accompanying drawings, in which Figure 1 is a vertical sectionof a manhole cover constructed according to my invention. Fig. 2 1s atop plan of thesame. Fig. 3 1s a bottom plan of the same.

In the construction shown the cover consists of a circular frame 2,having a flat base 3, with a central aperture 4 through same. The edgesof the aperture 4: are surrounded by a vertical wall 5, stiffened byweb-shaped braces 6. An annular shoulder 8 projects inwardly of theaperture 4, and extends around the wall 5 near the top of same. Theaperture 4 is closed by means of a cover-plate 9, which fits flush withthe upper edge of the wall 5 and rests upon the shoulder 8, as shown inFig. 1. A finger 10 is cast solid upon the cover-plate 9 at one side ofsame, and extends downwardly and outwardly, so as to bear on the underside of the shoulder 8 when the cover-plate 9 is in position. A dog 11is mounted on the plate 9 at a point diametrically opposite the finger10 and is adapted. to be turned into and out of engagement with theshoulder 8. The lower face of the shoulder 8 is beveled, as shown inFig. 1, and the arm 12 of the dog 11 is correspondingly beveled, so thatwhile the cover-' plate will be held tightly in place when the dog is inthe position shown in Fig. 1 the dog may be readily turned into and outof its locking position. The shank 13 of the dog is integral with thehead 14 of the arm 12, and the dog is seated in an aperture which is soformed that the head 14 of the dog will be flush with the top of thecover-plate 9.

In constructing the device the frame 2 and the cover-plate 9 arepreferably cast, while the dog is made in the form of a straight pinhavinga head 1 1 of a desired form. The pin turned, by means of asuitable wrench, so as to remove the arm 12 from engagement with theshoulder 8, when the plate 9 may be read;

To remove the cover-plate 9, the dog 11 is ily tilted upon the edge 16to release the finger 10 from said shoulder.

For the purpose of strengthening the coverplate 9 it is reinforced by aboss 17 surrounding the hole 15, and an annular rib 18, connecting theboss 15 and the finger 10.

It will be seen that some of the details of the construction shown maybe altered without departing from the spirit of my invention. Itherefore do not confine myself to such details except as hereinafterlimited in the claim.

hat I claim as my invention, and desire to secure by Letters Patent,is-- A manhole-cover, comprising a frame having a central aperture, andan inwardly-projecting annular shoulder on the wall of the aperture, thelower face of said shoulder being upwardly inclined, a cover-platefitting in said aperture, a lug at one side of the coverplate adapted toengage the lower face of said shoulder, an integral boss at the oppositeside of said cover-plate and a dog rotatably mounted in said boss, saiddogc'omprising a shank extending through said cover-plate having anintegral head on its upper end and being bent laterally below saidcover-plate to form an arm, said arm being, adapted to engage the saidinclined shoulder.

Signed at Chicago this 11th day of Janu-

